scholarly journals Differential Activation of Epidermal Growth Factor (EGF) Receptor Downstream Signaling Pathways by Betacellulin and EGF

Endocrinology ◽  
2004 ◽  
Vol 145 (9) ◽  
pp. 4232-4243 ◽  
Author(s):  
Tsugumichi Saito ◽  
Shuichi Okada ◽  
Kihachi Ohshima ◽  
Eijiro Yamada ◽  
Minoru Sato ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Signaling Pathways ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Chinese Hamster Ovary Cells ◽  
Inhibitory Effect ◽  
Erk Activation ◽  
Downstream Signaling ◽  
Epidermal Growth

Abstract To determine the downstream signaling pathways regulated by betacellulin (BTC) in comparison with epidermal growth factor (EGF), we used Chinese hamster ovary cells overexpressing the human EGF receptor (ErbB1/EGFR). The overall time-dependent activation of EGFR autophosphorylation was identical in cells treated with 1 nm BTC or 1.5 nm EGF. Analysis of site-specific EGFR phosphorylation demonstrated that the BTC and EGF tyrosine phosphorylation of Y1086 was not significantly different. In contrast, the autophosphorylation of Y1173 was markedly reduced in BTC-stimulated cells, compared with EGF stimulation that directly correlated with a reduced BTC stimulation of Shc tyrosine phosphorylation, Ras, and Raf-1 activation. On the other hand, Y1068 phosphorylation was significantly increased after BTC stimulation, compared with EGF in parallel with a greater extent of Erk phosphorylation. Expression of a dominant interfering MEK kinase 1 (MEKK1) and Y1068F EGFR more efficiently blocked the enhanced Erk activation by BTC, compared with EGF. Interestingly BTC had a greater inhibitory effect on apoptosis, compared with EGF, and expression of Y1068F EGFR abolished this enhanced inhibitory effect. Together, these data indicated that although BTC and EGF share overlapping signaling properties, the ability of BTC to enhance Erk activation occurs independent of Ras. The increased BTC activation results from a greater extent of Y1068 EGFR tyrosine phosphorylation and subsequent increased recruitment of the Grb2-MEKK1 complex to the plasma membrane, compared with EGF stimulation. The increased Erk activation by BTC associated with antiapoptotic function.

Involvement of Shc in insulin- and epidermal growth factor-induced activation of p21ras

1994 ◽  
Vol 14 (3) ◽  
pp. 1575-1581
Author(s):  
G J Pronk ◽  
A M de Vries-Smits ◽  
L Buday ◽  
J Downward ◽  
J A Maassen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Nucleotide Exchange ◽  
Similar Time ◽  
Epidermal Growth

Shc proteins are phosphorylated on tyrosine residues and associate with growth factor receptor-bound protein 2 (Grb2) upon treatment of cells with epidermal growth factor (EGF) or insulin. We have studied the role of Shc in insulin- and EGF-induced activation of p21ras in NIH 3T3 cells overexpressing human insulin receptors (A14 cells). A14 cells are equally responsive to insulin and EGF with respect to activation of p21ras. Analysis of Shc immunoprecipitates revealed that (i) both insulin and EGF treatment resulted in Shc tyrosine phosphorylation and (ii) Shc antibodies coimmunoprecipitated both Grb2 and mSOS after insulin and EGF treatment. The induction of tyrosine phosphorylation of Shc and the presence of Grb2 and mSOS in Shc immunoprecipitates followed similar time courses, with somewhat higher levels after EGF treatment. In mSOS immunoprecipitates, Shc could be detected as well. Furthermore, Shc immune complexes contained guanine nucleotide exchange activity toward p21ras in vitro. From these results, we conclude that after insulin and EGF treatment, Shc associates with both Grb2 and mSOS and therefore may mediate, at least in part, insulin- and EGF-induced activation of p21ras. In addition, we investigated whether the Grb2-mSOS complex associates with the insulin receptor or with insulin receptor substrate 1 (IRS1). Although we observed association of Grb2 with IRS1, we did not detect complex formation between mSOS and IRS1 in experiments in which the association of mSOS with Shc was readily detectable. Furthermore, whereas EGF treatment resulted in the association of mSOS with the EGF receptor, insulin treatment did not result in the association of mSOS with the insulin receptor. These results indicate that the association of Grb2-nSOS with Shc may be an important event in insulin-induced, mSOS-mediated activation of p21ras.

Evidence for epidermal growth factor (EGF)-induced intermolecular autophosphorylation of the EGF receptors in living cells

1990 ◽  
Vol 10 (8) ◽  
pp. 4035-4044
Author(s):  
A M Honegger ◽  
A Schmidt ◽  
A Ullrich ◽  
J Schlessinger
Keyword(s):  
Signal Transduction ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Living Cells ◽  
Egf Receptors ◽  
Receptor Molecule ◽  
Epidermal Growth ◽  
Negative Mutant

In response to epidermal growth factor (EGF) stimulation, the intrinsic protein tyrosine kinase of EGF receptor is activated, leading to tyrosine phosphorylation of several cellular substrate proteins, including the EGF receptor molecule itself. To test the mechanism of EGF receptor autophosphorylation in living cells, we established transfected cell lines coexpressing a kinase-negative point mutant of EGF receptor (K721A) with an active EGF receptor mutant lacking 63 amino acids from its carboxy terminus. The addition of EGF to these cells caused tyrosine phosphorylation of the kinase-negative mutant by the active receptor molecule, demonstrating EGF receptor cross-phosphorylation in living cells. After internalization the kinase-negative mutant and CD63 have separate trafficking pathways. This limits their association and the extent of cross-phosphorylation of K721A by CD63. The coexpression of the kinase-negative mutant together with active EGF receptors in the same cells suppressed the mitogenic response toward EGF as compared with that in cells that express active receptors alone. The presence of the kinase-negative mutant functions as a negative dominant mutation suppressing the response of active EGF receptors, probably by interfering with EGF-induced signal transduction. It appears, therefore, that crucial events of signal transduction occur before K721A and active EGF receptors are separated by their different endocytic itineraries.

scholarly journals Phosphorylation and activation of epidermal growth factor receptors in cells transformed by the src oncogene.

1991 ◽  
Vol 11 (1) ◽  
pp. 309-321 ◽  
Author(s):  
W J Wasilenko ◽  
D M Payne ◽  
D L Fitzgerald ◽  
M J Weber
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Phospholipase C ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Growth Factor Receptors ◽  
Epidermal Growth ◽  
Phospholipase C Gamma ◽  
Signaling Activity ◽  
In Cells

Because functionally significant substrates for the tyrosyl protein kinase activity of pp60v-src are likely to include membrane-associated proteins involved in normal growth control, we have tested the hypothesis that pp60v-src could phosphorylate and alter the signaling activity of transmembrane growth factor receptors. We have found that the epidermal growth factor (EGF) receptor becomes constitutively phosphorylated on tyrosine in cells transformed by the src oncogene and in addition displays elevated levels of phosphoserine and phosphothreonine. High-performance liquid chromatography phosphopeptide mapping revealed two predominant sites of tyrosine phosphorylation, both of which differed from the major sites of receptor autophosphorylation; thus, the src-induced phosphorylation is unlikely to occur via an autocrine mechanism. To determine whether pp60v-src altered the signaling activity of the EGF receptor, we analyzed the tyrosine phosphorylation of phospholipase C-gamma, since phosphorylation of this enzyme occurs in response to activation of the EGF receptor but not in response to pp60v-src alone. We found that in cells coexpressing pp60v-src and the EGF receptor, phospholipase C-gamma was constitutively phosphorylated, a result we interpret as indicating that the signaling activity of the EGF receptor was altered in the src-transformed cells. These findings suggest that pp60v-src-induced alterations in phosphorylation and function of growth regulatory receptors could play an important role in generating the phenotypic changes associated with malignant transformation.

Targeting epidermal growth factor receptors and downstream signaling pathways in cancer by phytochemicals

2014 ◽  
Vol 10 (3) ◽  
pp. 337-353 ◽  
Author(s):  
Onat Kadioglu ◽  
Jingming Cao ◽  
Mohamed E. M. Saeed ◽  
Henry Johannes Greten ◽  
Thomas Efferth
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Signaling Pathways ◽  
Growth Factor Receptors ◽  
Epidermal Growth Factor Receptors ◽  
Downstream Signaling ◽  
Epidermal Growth

scholarly journals Epidermal Growth Factor-Induced Heterologous Desensitization of the Luteinizing Hormone/Choriogonadotopin Receptor in a Cell-Free Membrane Preparation Is Associated with the Tyrosine Phosphorylation of the Epidermal Growth Factor Receptor**This work was supported by USDA Grant NRICGP-9401432 (to M.H.D.).

Endocrinology ◽  
1999 ◽  
Vol 140 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Marilyn L. G. Lamm ◽  
Rajsree M. Rajagopalan-Gupta ◽  
Mary Hunzicker-Dunn
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Adenylyl Cyclase ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Cyclase Activity ◽  
Adenylyl Cyclase Activity ◽  
Heterologous Desensitization ◽  
Dependent Protein ◽  
Epidermal Growth

Abstract Epidermal growth factor (EGF) attenuated hCG-stimulated adenylyl cyclase activity in rat luteal and follicular membranes. H7, an equipotent serine/threonine protein kinase inhibitor of cAMP-dependent protein kinases, cGMP-dependent protein kinases, and lipid-dependent protein kinase C, did not effect the ability of EGF to decrease hCG-responsive adenylyl cyclase activity, suggesting that a serine/threonine phosphorylation event catalyzed by these kinases was not critically involved in EGF-induced desensitization. Likewise, pertussis toxin-catalyzed ADP-ribosylation of a 40-kDa luteal membrane protein, which exhibited immunoreactivity with an antibody against Giα, did not hinder the ability of EGF to attenuate hCG-stimulated adenylyl cyclase activity, indicating that Gi did not mediate EGF-induced desensitization. Rather, EGF-induced heterologous desensitization of LH/CG receptor in ovarian membranes was closely associated with the specific and prominent tyrosine phosphorylation of the 170-kDa EGF receptor. Both EGF-stimulated autophosphorylation of EGF receptor and EGF-induced LH/CG receptor desensitization were attenuated by genistein, a tyrosine kinase inhibitor. These results suggest that tyrosine phosphorylation of the 170-kDa EGF receptor is a necessary component of the signaling pathway in EGF-induced heterologous desensitization of the LH/CG receptor.

scholarly journals The Inhibitory Effect of ErbB2 on Epidermal Growth Factor-induced Formation of Clathrin-coated Pits Correlates with Retention of Epidermal Growth Factor Receptor-ErbB2 Oligomeric Complexes at the Plasma Membrane

2005 ◽  
Vol 16 (12) ◽  
pp. 5832-5842 ◽  
Author(s):  
Camilla Haslekås ◽  
Kamilla Breen ◽  
Ketil W. Pedersen ◽  
Lene E. Johannessen ◽  
Espen Stang ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Inhibitory Effect ◽  
Coated Pits ◽  
Transfected Cells ◽  
Epidermal Growth

By constructing stably transfected cells harboring the same amount of epidermal growth factor (EGF) receptor (EGFR), but with increasing overexpression of ErbB2, we have demonstrated that ErbB2 efficiently inhibits internalization of ligand-bound EGFR. Apparently, ErbB2 inhibits internalization of EGF-bound EGFR by constitutively driving EGFR-ErbB2 hetero/oligomerization. We have demonstrated that ErbB2 does not inhibit phosphorylation or ubiquitination of the EGFR. Our data further indicate that the endocytosis deficiency of ErbB2 and of EGFR-ErbB2 heterodimers/oligomers cannot be explained by anchoring of ErbB2 to PDZ-containing proteins such as Erbin. Instead, we demonstrate that in contrast to EGFR homodimers, which are capable of inducing new clathrin-coated pits in serum-starved cells upon incubation with EGF, clathrin-coated pits are not induced upon activation of EGFR-ErbB2 heterodimers/oligomers.

scholarly journals Temperature-dependent tyrosine phosphorylation of microtubule-associated protein kinase in epidermal growth factor-stimulated human fibroblasts.

1991 ◽  
Vol 2 (8) ◽  
pp. 663-673 ◽  
Author(s):  
R Campos-González ◽  
J R Glenney
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Map Kinase ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Human Fibroblasts ◽  
C Terminus ◽  
Epidermal Growth

Treatment of normal human fibroblasts with epidermal growth factor (EGF) results in the rapid (0.5 min) and simultaneous tyrosine phosphorylation of the EGF receptor (EGFr) and several other proteins. An exception to this tyrosine phosphorylation wave was a protein (42 kDa) that became phosphorylated on tyrosine only after a short lag time (5 min). We identified this p42 kDa substrate as the microtubule-associated protein (MAP) kinase using a monoclonal antibody to a peptide corresponding to the C-terminus of the predicted protein (Science 249, 64-67, 1990). EGF treatment of human fibroblasts at 37 degrees C for 5 min resulted in the tyrosine phosphorylation of 60-70% of MAP kinase as determined by the percent that was immunoprecipitated with antiphosphotyrosine antibodies. Like other tyrosine kinase growth factor receptors, the EGFr is activated and phosphorylated at 4 degrees C but is not internalized. Whereas most other substrates were readily tyrosine phosphorylated at 4 degrees C, MAP kinase was not. When cells were first stimulated with EGF at 4 degrees C and then warmed to 37 degrees C without EGF, tyrosine phosphorylation of MAP kinase was again observed. Treatment of cells with the protein kinase C activator phorbol myristate acetate (PMA) also resulted in the tyrosine phosphorylation of MAP kinase, and again only at 37 degrees C. Tryptic phosphopeptide maps demonstrated that EGF and PMA both induced the phosphorylation of the same peptide on tyrosine and threonine. This temperature and PMA sensitivity distinguishes MAP kinase from most other tyrosine kinase substrates in activated human fibroblasts.

scholarly journals Tyrosine Phosphorylation of the c-cblProto-oncogene Protein Product and Association with Epidermal Growth Factor (EGF) Receptor upon EGF Stimulation

1995 ◽  
Vol 270 (35) ◽  
pp. 20242-20245 ◽  
Author(s):  
Maria L. Galisteo ◽  
Ivan Dikic ◽  
Andreas G. Batzer ◽  
Wallace Y. Langdon ◽  
Joseph Schlessinger
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Protein Product ◽  
Epidermal Growth ◽  
Oncogene Protein

scholarly journals Participation of both Gab1 and Gab2 in the activation of the ERK/MAPK pathway by epidermal growth factor

2005 ◽  
Vol 391 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Songshu Meng ◽  
Zhengming Chen ◽  
Teresita Munoz-Antonia ◽  
Jie Wu
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mapk Pathway ◽  
Inhibitory Effect ◽  
Similar Amount ◽  
Small Interfering Rnas ◽  
Erk Activation ◽  
Activation Pathway ◽  
Docking Proteins ◽  
Epidermal Growth

Three members of Gab family docking proteins, Gab1, Gab2 and Gab3, have been identified in humans. Previous studies have found that the hepatocyte growth factor preferentially utilizes Gab1 for signalling, whereas Bcr-Abl selectively signals through Gab2. Gab1–SHP2 interaction has been shown to mediate ERK (extracellular-signal-regulated kinase) activation by EGF (epidermal growth factor). However, it was unclear whether EGF selectively utilizes Gab1 for signalling to ERK and whether Gab2 is dispensable in cells where Gab1 and Gab2 are co-expressed. Using T47D and MCF-7 human breast carcinoma cells that express endogenous Gab1 and Gab2, we examined the role of these docking proteins in EGF-induced ERK activation. It was found that EGF induced a similar amount of SHP2–Gab1 and SHP2–Gab2 complexes. Expression of either SHP2-binding defective Gab1 or Gab2 mutant blocked EGF-induced ERK activation. Down-regulation of either Gab1 or Gab2 by siRNAs (small interfering RNAs) effectively inhibited the EGF-stimulated ERK activation pathway and cell migration. Interestingly, the inhibitory effect of Gab1 siRNA could be rescued not only by expression of an exogenous mouse Gab1 but also by an exogenous human Gab2 and vice versa, but not by IRS1 (insulin receptor substrate 1). These results reveal that Gab2 plays a pivotal role in the EGF-induced ERK activation pathway and that it can complement the function of Gab1 in the EGF signalling pathway. Furthermore, Gab1 and Gab2 are critical signalling threshold proteins for ERK activation by EGF.

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